Returned international travellers who refuse to be tested for COVID-19 on the 10th day of hotel quarantine in NSW will be made to extend their stay by an extra 10 days.
It comes as six new cases are reported in the state on Saturday, including a man in his 70s from Sydney's west.
All close contacts of the man, from the Penrith area, have been contacted and the case is under investigation, NSW Health said.
The remaining five new cases are returned travellers in hotel quarantine, the department said in a statement.
Less than two per cent of returned travellers in hotel quarantine have refused to take a coronavirus test on the 10th day of their stay, NSW Health said.
"NSW will ensure all returned international travellers entering Australia will either be tested for COVID-19 during their hotel quarantine at day 10, or be required to extend their quarantine by an extra 10 days," the department said in a statement on Saturday.
"NSW already requests all of these returned travellers undertake a COVID-19 test on day 10 of their quarantine, and less than two per cent have refused to take the test."
Testing on day 10 was established by NSW Health on May 15, and since then 59 of 11,634 returned travellers have been found to be positive.
They are in addition to the 3,314 returned travellers who displayed symptoms and were tested in quarantine hotels before or after day 10.
Since March 29, 105 of these symptomatic returned travellers have tested positive.
The six cases reported on Saturday bring the state's total number of coronavirus cases to 3,174. A total of 58 cases are being treated by NSW Health, with none in intensive care.
International travellers refusing tests in Victoria
Meanwhile in Victoria about 30 per cent of international travellers were refusing to be tested while in quarantine, Victoria's Deputy Chief Health Officer Annaliese van Diemen revealed on Friday.
Liberal MP Trent Zimmerman was shocked by the figures.
"Frankly, I think it is recklessly indifferent of people in quarantine not to agree to have a test, because we've seen the number of people that are in quarantine testing positive is obviously a lot higher than the rest of the population," he told ABC television on Saturday.
Labor frontbencher Linda Burney thought their actions were "really selfish".
"The reason that Australia is doing relatively well in terms of the virus is because of the testing regimes and we know how important they are," she told ABC television.
Melbourne remains a worrying coronavirus hotspot and testing is being ramped up as Victoria enters the school holidays.
Victoria recorded 30 new COVID-19 cases on Friday, its 10th continuous day of double-digit infections.
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